There is known a technology of providing virtual reality with use of a head-mounted device (HMD). Further, there is proposed a technology of arranging respective avatars of a plurality of users in a virtual space for communication among the plurality of users via those avatars.
As a technology of enhancing communication using avatars, there is known a technology of detecting a motion of a face of a user by a face-tracking technology (Patent Documents 1 to 3) and reflecting the detected motion of the face in an avatar. For example, in Patent Document 1, there is described a technology of detecting a motion of a mouth of a user by pattern matching.